1. Technical Field
The present invention relates to a pulse motor driving device, a pulse motor driving method, a timepiece device, and a timepiece device control method, and a-more particularly, to a device for driving a pulse motor used in, for example, an analog timepiece having a magnetic generator, and to a method for driving such a pulse motor, and to a timepiece device, such as an analog timepiece, and to a method for controlling such a timepiece device.
2. Background Art
Recent years have seen remarkable technological innovations in timepiece devices (that is, electronic timepieces), such as a wristwatch. The power consumption of the presently used timepiece devices has come to be suppressed to about 0.5 xcexcW. Incidentally, the breakdown of power consumption of such a timepiece device is considered as follows. The power consumption of an electric circuit system of the timepiece device is 20 percent of that of the entire device. The power consumption of a pulse motor for moving hands of the device accounts for the remaining 80 percent of that of the entire device. Reduction of the power consumption of this pulse motor is, therefore, considered as the key to a further reduction of the power consumption of the device.
Thus, the conventional timepiece device (or electric timepiece) has a part configured in such a manner as to operate as follows. That is, after supplying a driving current to the pulse motor, the part detects whether or not the pulse motor is actually rotated by the driving current. If not, the timepiece device forces the pulse motor to rotate, and increases a driving current to be supplied thereto the next time. However, after the lapse of a predetermined time, the timepiece device decreases a driving current. Consequently, the effective value of the magnitude of the driving current to be supplied to the pulse motor is a value, at which the frequency of increasing the power consumption of the pulse motor and that of decreasing the power consumption thereof are in balance, that is, a value close to the lowest value of the driving current, at which the pulse motor can rotate, from a macroscopic viewpoint. This enables suppression of excessive power consumption of the pulse motor. Thus, the power consumption of the pulse motor is reduced.
However, recently, it has been pointed out that a magnetic field generated outside the timepiece adversely affects the rotation of the pulse motor. That is, as above described, the effective value of the magnitude of the driving current to be supplied to the pulse motor is obtained as a value, at which the frequency of increasing the power consumption of the pulse motor and that of decreasing the power consumption thereof are in balance, close to the lowest value thereof. When an external magnetic field is applied to the pulse motor, to which the driving current, whose magnitude is the effective value, is supplied, the magnitude of a magnetic field generated by the driving current is reduced, with the result that the pulse motor does not rotate.
Further, recently, electronic timepieces each having a built-in generator for generating electric power are coming on the market. In brief, such a generator converts a reciprocating motion, such as a swinging motion of a hand, to a rotary motion, and then transmits this rotary motion to a magnetized rotor to thereby cause an electromotive force in a coil. Thus, a magnetic field generated in a timepiece body adversely affects the rotation of the pulse motor.
Moreover, the serious influence of the magnetic field is not limited to the fact that the pulse motor does not rotate. As described above, the electronic timepiece has a part adapted to detect whether or not the pulse motor actually rotates, after supplying a driving current to the pulse motor. Although such a detecting part may be constituted by a mechanical device, an electrical device, which detects the rotation of the pulse motor according to whether or not an electric current is induced in the coil thereof as damped oscillations are caused after the rotation thereof, is suitable for such a detecting part, in view of the spatial constraints on the timepiece body.
However, even when the rotation of the pulse motor is electrically detected, if a magnetic field is generated, an induced current caused by the magnetic field is superposed on the coil in addition to the induced current caused due to the damped oscillations. Thus, although the pulse motor does not rotate actually, the detecting part may erroneously detect that the pulse motor rotates.
As described above, to reduce the power consumption of the electronic timepiece, the effective value of the magnitude of the driving current is lowered after the lapse of the predetermined time. When the effective value of the magnitude of the driving current is lowered, naturally, the pulse motor is liable to enter a non-rotation state. Incidentally, the probability of an occurrence of the erroneous detection is represented by a ratio of the frequency of an occurrence of the case, in which the pulse motor is detected as not rotating actually, to the frequency of an occurrence of the case, in which the pulse motor is detected as rotating. Therefore, when the pulse motor is apt to enter the non-rotation state, the numerator of this ratio increases, so that the probability of an occurrence of the erroneous detection rises. Further, when an erroneous detection actually occurs, the forced rotation of the pulse motor is not caused. This has an important influence on the time indication accuracy of the timepiece. That is, the conventional electronic timepiece enabled to reduce the power consumption has a drawback in that such accuracy is extremely deteriorated.
To eliminate this drawback, a first example of the conventional timepiece device, namely, an analog electronic timepiece, which has a generator and is described in the PCT international publication No. WO98/41906 Official Gazette, is adapted to output a correction driving pulse signal, whose effective power level is high, for the purpose of moving hands with reliability, during an operating time for moving hands, in the case that the power generation of the generator is detected. Furthermore, in the case that the correction driving pulse is outputted, a demagnetizing pulse signal is outputted so as to reduce a magnetic field generated in response to the correction driving pulse whose effective power level is high.
Moreover, a second example of the conventional timepiece device, namely, another analog electronic timepiece having a generator, which has a generator and is described in the European Patent Application Publication No. EP-0704774-A1 Official Gazette, is adapted to output a normal driving pulse signal, whose effective power level is lower, by periodically lowering the duty ratio of the normal driving pulse signal so as to reduce the power consumption thereof.
Furthermore, to reduce the power consumption and the electric power of the pulse motor, a normal driving pulse signal, whose number of constituent pulses (hereunder referred to as the xe2x80x9cnumber of teethxe2x80x9d) included during a time period for outputting the normal driving pulse signal are reduced and whose effective power level is low, is outputted when it is decided that the voltage of a capacitor is higher than a predetermined voltage. Conversely, when it is decided that the voltage of the capacitor is lower than the predetermined voltage, a normal driving pulse signal, whose xe2x80x9cnumber of teethxe2x80x9d is increased and whose effective power level is high, is outputted. Further, when the xe2x80x9cnumber of teethxe2x80x9d of the normal driving pulse signal should be changed, the xe2x80x9cnumber of teethxe2x80x9d is changed without altering the duty ratio used at the last hand movement.
In the case of the first example of the conventional timepiece device, the effective power level of the correction driving pulse signal is high, so that the power consumption of the pulse motor is large. Especially, the conventional analog electronic timepiece having the generator has a drawback in that a time period, in which hands are continuously moved, is shorten when the number of times of outputting the correction driving pulse signal is large.
Furthermore, the influence of the residual magnetic field sometimes cannot be canceled owing to the high effective power level of the correction driving pulse signal, even when the demagnetizing pulse signal is outputted. Further, in such a case, the loss of a normal driving pulse signal at the next hand movement is decreased owing to the influence of the residual magnetic field, so that the substantial effective power level is lowered. Thus, the probability of an occurrence of the non-rotation state of the hand driving motor is increased. The conventional timepiece device has another drawback in that the probability of an occurrence of what is called a hand movement failure increases, namely, there is an increase in the probability of an occurrence of an erroneous affirmative decision on the rotation of the hand driving motor during the detection of the rotation of this hand driving motor, in spite of the actual non-rotation state of this motor, when noises are generated in the generator, in such a case.
Additionally, in the case of the second example of the conventional timepiece device, the duty ratio is lowered at this alteration thereof even in the case that the duty ratio is set at the lowest limit duty ratio value which is the lower limit value that enables the driving of the hand driving motor at the last alteration of the duty ratio of the normal driving signal. Thus, the conventional timepiece device has another drawback in that the hand driving motor cannot rotate at the next alteration of the duty ratio.
In such a case, a correction driving pulse signal, whose effective power level is high, is outputted so as to ensure reliable hand movement. Thus, the conventional timepiece device has another drawback in that the power consumption of the pulse motor increases and that the probability of an occurrence of the aforementioned hand movement failure.
Furthermore, the aforementioned second example of the conventional timepiece device has the following effects of changing the xe2x80x9cnumber of teethxe2x80x9d of the normal driving pulse signal without changing the duty ratio at the last alteration thereof
That is, first, the following first and second curves are assumed in view of the relation between the power supply voltage and the duty ratio in an operating region of the hand driving motor, which is indicated correspondingly to each value of the xe2x80x9cnumber of teethxe2x80x9d of the normal driving pulse signal. Namely, the first curve represents the lower limit value of the power supply voltage at which the hand driving motor operates at each value of the duty ratio when the xe2x80x9cnumber of teethxe2x80x9d of the normal driving pulse signal is a first xe2x80x9cnumber of teethxe2x80x9d, while the second curve represents the lower limit value of the power supply voltage at which the hand driving motor operates at each value of the duty ratio when the xe2x80x9cnumber of teethxe2x80x9d of the normal driving pulse signal is a second xe2x80x9cnumber of teethxe2x80x9d (which is less than the first xe2x80x9cnumber of teethxe2x80x9d). In such a case, although it is considered according to the first curve that a duty ratio belongs to an operating region, this duty ratio may belong to a non-operating region when considered according to the second curve.
Therefore, a case, in which the hand driving motor neither operates nor rotates when the xe2x80x9cnumber of teethxe2x80x9d of the normal driving pulse signal is changed, may occur. The conventional timepiece device has another drawback in that the probability of an occurrence of what is called the hand movement failure increases. Namely, there is an increase in the probability of an occurrence of an erroneous affirmative decision on the rotation of the hand driving motor during the detection of the rotation of this hand driving motor, in spite of the actual non-rotation state of this motor, when noises are generated in the generator, in such a case, increases in such a case.
Accordingly, an object of the present invention is to provide a device and method for driving a pulse motor, which can reduce the power consumption of the pulse motor and can enhance the timing accuracy, and a timepiece device employing such a device, and a method for controlling such a timepiece device.
According to a first aspect of the present invention, there is provided a pulse motor driving device, which comprises a magnetic field detecting unit for detecting a magnetic field in the vicinity of the pulse motor, a control unit for controlling an effective value of the driving power of the pulse motor, and a rotation detecting unit for detecting whether or not the pulse motor rotates. The control unit is adapted to perform an operation of increasing the effective value of the driving power of the pulse motor when it is detected by the rotation detecting unit that the pulse motor does not rotate, and periodically performs an operation of lowering the effective value of the driving power thereof. Further, the control unit is adapted to interrupt the operation of lowering the effective value of the driving power of the pulse motor when a magnetic field is detected by the magnetic detecting unit.
Moreover, the control unit of the device according to the first aspect of the present invention may increase and decrease an effective value of a driving current when the effective value of the driving power is increased and decreased.
Further, the control unit of the device according to the first aspect of the present invention may increase and decrease an effective value of a driving voltage when the effective value of the driving power is increased and decreased.
Furthermore, the control unit of the device according to the first aspect of the present invention may increase and decrease a duty ratio of a driving pulse for driving of the pulse motor when the effective value of the driving power is increased and decreased.
Further, the control unit of the device according to the first aspect of the present invention may increase and decrease the number of driving pulses, which are used for driving the pulse motor, per unit time when the effective value of the driving power is increased and decreased.
Moreover, the control unit of the device according to the first aspect of the present invention may forcedly cause the pulse motor to rotate, when a magnetic field is detected by the magnetic field detecting unit.
Furthermore, the control unit of the device according to the first aspect of the present invention may stop the supply of a drive current, whose effective value is controlled, to the pulse motor, when a magnetic field is detected by the magnetic field detecting unit.
Further, the control unit of the device according to the first aspect of the present invention may forcedly cause the pulse motor to rotate, when it is detected by the rotation detecting unit that the pulse motor does not rotate.
Moreover, the device according to the first aspect of the present invention may have a counting unit for performing a counting operation in a constant cycle. The counting unit may reset a count to an initial value or interrupt a counting operation when a magnetic field is detected by the magnetic detecting unit. The control unit may perform an operation of lowering an effective value of the driving power when the count reaches a predetermined value.
Furthermore, the rotation detecting unit of the device according to the first aspect of the present invention may detect according to electric current induced in a coil of the pulse motor whether not the pulse motor rotates.
Further, the magnetic field detecting unit of the device according to the first aspect of the present invention may detect a magnetic field according to electric current induced in a coil of the pulse motor.
Moreover, the magnetic field detecting unit of the device according to the first aspect of the present invention may detect a magnetic field, which is present in the vicinity of the pulse motor, before a driving current is supplied to the pulse motor. Upon completion of supplying the driving current to the pulse motor, the rotation detecting unit thereof may detect whether or not the pulse motor rotates.
Furthermore, the device according to the first aspect of the present invention may have a power generating unit for generating power and supplying driving power to the pulse motor. The magnetic field detecting unit may detect a magnetic field in the vicinity of the pulse motor by directly or indirectly detecting the state of an electric current, which is caused by generating electric power.
Further, the device according to the first aspect of the present invention may have a power generating unit for generating power and supplying driving power to the pulse motor, and a power storing unit for storing electric power generated by the power generating unit. The magnetic field detecting unit may detect a magnetic field in the vicinity of the pulse motor by directly or indirectly detecting the state of a power storage current, which is caused by storing electric charges in the power storing unit.
Moreover, the magnetic field detecting unit of the device according to the first aspect of the present invention may have a magnetic sensor for detecting a magnetic field in the vicinity of the pulse motor.
According to a second aspect of the present invention, there is provided a pulse motor driving device, which comprises a magnetic field detecting circuit for detecting a magnetic field in the vicinity of a pulse motor, a control circuit for controlling an effective value of the driving power of the pulse motor, and a rotation detecting circuit for detecting whether or not the pulse motor rotates. The control unit is adapted to perform an operation of increasing the effective value of the driving power of the pulse motor and periodically performs an operation of lowering the effective value of the driving power thereof when it is detected by the rotation detecting circuit that the pulse motor does not rotate. Further, the control unit is adapted to interrupt the operation of lowering the effective value of the driving power of the pulse motor when a magnetic field is detected by the magnetic detecting circuit.
Moreover, the rotation detecting circuit of the device according to the second aspect of the present invention may detect according to electric current induced by the rotation of the pulse motor whether not the pulse motor rotates.
Furthermore, the control circuit of the device according to the second aspect of the present invention may increase and decrease an effective value of a driving current when the effective value of the driving power is increased and decreased.
According to a third aspect of the present invention, there is provided a pulse motor driving method, which comprises the steps of detecting a magnetic field in the vicinity of a pulse motor, and controlling an effective value of the driving power of the pulse motor, and detecting whether or not the pulse motor rotates. This method further comprises the steps of performing an operation of increasing the effective value of the driving power of the pulse motor, and periodically performing an operation of lowering the effective value of the driving power thereof when it is detected by the rotation detecting circuit that the pulse motor does not rotate. Further, this method further comprises the steps of interrupting the operation of lowering the effective value of the driving power of the pulse motor when a magnetic field is detected by the magnetic detecting circuit.
Moreover, in the case of the method according to the third aspect of the present invention, an effective value of a driving current may be increased and decreased when the effective value of the driving power is increased and decreased.
Further, in the case of the method according to the third aspect of the present invention, an effective value of a driving voltage may be increased and decreased when the effective value of the driving power is increased and decreased.
Furthermore, in the case of the method according to the third aspect of the present invention, a duty ratio of a driving pulse for driving of the pulse motor may be increased and decreased when the effective value of the driving power is increased and decreased.
Further, in the case of the method according to the third aspect of the present invention may increase and decrease the number of driving pulses, which are used for driving the pulse motor, per unit time when the effective value of the driving power is increased and decreased.
Moreover, in the case of the method according to the third aspect of the present invention, the pulse motor may be forced to rotate, when a magnetic field is detected.
Furthermore, in the case of the method according to the third aspect of the present invention, the supply of a drive current, whose effective value is controlled, to the pulse motor may be stopped, when a magnetic field is detected.
Further, in the case of the method according to the third aspect of the present invention, the pulse motor may be forced to rotate, when it is detected that the pulse motor does not rotate.
Moreover, in the case of the method according to the third aspect of the present invention, a counting operation may be performed in a constant cycle. A count may be reset to an initial value or a counting operation may be interrupted, when a magnetic field is detected. An operation of lowering an effective value of the driving power may be performed when the count reaches a predetermined value.
Furthermore, in the case of the method according to the third aspect of the present invention, it may be detected according to electric current induced in a coil of the pulse motor whether not the pulse motor rotates.
Further, in the case of the method according to the third aspect of the present invention, a magnetic field may be detected according to electric current induced in a coil of the pulse motor.
Moreover, in the case of the method according to the third aspect of the present invention, a magnetic field, which is present in the vicinity of the pulse motor, may be detected before a driving current is supplied to the pulse motor. It may be detected upon completion of supplying the driving current to the pulse motor whether or not the pulse motor rotates.
Furthermore, the method according to the third aspect of the present invention may further comprises the step of generating power so as to supply driving power to the pulse motor. A magnetic field may be detected in the vicinity of the pulse motor by detecting an amount of electric current caused by generating electric power.
Further, the method according to the third aspect of the present invention may further comprise the steps of generating electric power to supply driving power to the pulse motor, and storing the generated electric power, and detecting a magnetic field in the vicinity of the pulse motor by detecting an amount of power storage current, which is caused by generating electric power.
According to a fourth aspect of the present invention, there is provided a timepiece device, which comprises a pulse motor for performing an operation of moving hands, a magnetic field detecting unit for detecting a magnetic field in the vicinity of a pulse motor, a control unit for controlling an effective value of the driving power of the pulse motor, and a rotation detecting unit for detecting whether or not the pulse motor rotates. The control unit is adapted to perform an operation of increasing the effective value of the driving power of the pulse motor and periodically performs an operation of lowering the effective value of the driving power thereof when it is detected by the rotation detecting unit that the pulse motor does not rotate. Further, the control unit is adapted to interrupt the operation of lowering the effective value of the driving power of the pulse motor when a magnetic field is detected by the magnetic detecting unit, and adapted to force the pulse motor to rotate.
Moreover, the control unit of the device according to the fourth embodiment of the present invention may increase and decrease an effective value of a driving current when the effective value of the driving power is increased and decreased.
Further, the rotation detecting unit of the device according to the fourth aspect of the present invention may detect according to electric current induced by the rotation of the pulse motor whether not the pulse motor rotates.
Furthermore, the device according to the fourth aspect of the present invention may further comprise a power generating unit for generating electric power, and use an electromotive force caused by this unit as a driving force for the pulse motor.
Further, the power generating unit of the device according to the fourth aspect of the present invention may have a rotary weight for performing a turn movement, and a power generating element for generating an AC electromotive force by utilizing the turn movement of the rotary weight.
According to a fifth aspect of the present invention, there is provided a timepiece device having a motor, which is driven according to electric power supplied from an electromagnetic generator. This timepiece device comprises an AC magnetic field detecting unit for detecting an AC magnetic field generated around the electromagnetic generator, and a duty ratio control unit for controlling a duty ratio to be used to drive the motor according to a result of a detection by the AC magnetic field detecting unit. The duty ratio control unit has a duty ratio setting unit adapted to maintain the duty ratio of a normal driving pulse signal at a currently set value or set the duty ratio at a value, which is higher than the currently set value, when an AC magnetic field is detected by the AC magnetic field detecting unit.
Further, the device according to the fifth aspect of the present invention may further comprises a power storing unit for storing electric power supplied from the electromagnetic generator, and a charge detecting unit for detecting charging of the power storing unit. The AC magnetic field detecting unit detects an AC magnetic filed generated around the electromagnetic generator when the charge detecting unit detects a charge in a predetermined time period for detection.
Moreover, the device according to the fifth aspect of the present invention may further comprises a rotation detecting unit for detecting whether or not the motor rotates, and a correction driving pulse output unit for outputting a correction driving pulse signal, whose effective power level is higher than that of the normal driving pulse signal, when it is detected that the motor does not rotate.
Furthermore, the device according to the fifth aspect of the present invention may further comprise a demagnetizing pulse output unit for outputting a demagnetizing pulse signal to be used to demagnetize a residual magnetic field caused by the correction driving pulse signal that is outputted by the correction driving pulse signal output unit.
Further, in the case of the device according to the fifth aspect of the present invention, a start time of the predetermined time period for detection is a demagnetizing-pulse outputting moment, at which a demagnetizing pulse signal is outputted in the last hand movement operation time period, or included in a time period from a moment, which is just after the demagnetizing-pulse outputting moment, to a moment just before a normal driving pulse signal is outputted in a current hand movement operation time period. Moreover, a termination time of the predetermined time period for detection is included in a time period from the moment, which is just before a normal driving pulse signal is outputted in the current hand movement operation time period, to a moment just after the normal driving pulse signal is outputted.
Furthermore, the duty ratio setting unit of the device according to the fifth aspect of the present invention may maintain the duty ratio of a pulse, which is not outputted yet, at a currently set value or set the duty ratio of the pulse, which is not outputted yet, at a value that is higher than the currently set value.
Further, the device according to the fifth aspect of the present invention may further comprises a voltage detecting unit for detecting the voltage of the power storing unit, and a teeth number selection unit for selecting and changing the number of pulses of a normal driving pulse signal to be outputted in a time period therefor by comparing the voltage detected by the voltage detecting unit with a predetermined reference voltage.
Moreover, the teeth number selection unit of the device according to the fifth aspect of the present invention may select one of two numbers of pulses, which are switched from each other according to whether or not the detected voltage is higher than the reference voltage. That is, the teeth number selection unit selects a larger one of the two number of pulses when the detected voltage is lower than the reference voltage. Furthermore, the teeth number selection unit selects a smaller one of the two number of pulses when the detected voltage is higher than the reference voltage.
Furthermore, in the case of the device according to the fifth aspect of the present invention, a normal driving pulse signal corresponding to a larger one of the two numbers of pulses, which are to be switched from each other according to whether or not the detected voltage is higher than the reference voltage, is set in such a manner as to have a higher effective power level than that of a normal driving pulse signal corresponding to a smaller one of the two numbers of pulses.
According to a sixth aspect of the present invention, there is provided a timepiece device control method for controlling a timepiece device having a motor driven according to electric power, which is supplied from an electromagnetic generator. This method comprises the AC magnetic field detecting step of detecting an AC magnetic filed generated around the electromagnetic generator, and the duty ratio control step of controlling the step of controlling a duty ratio of a normal driving pulse signal, which is used for driving the motor, according to a result of detecting a magnetic field at the AC magnetic field detecting step. The duty ratio control step has a duty ratio setting step of maintaining the duty ratio of the normal driving pulse signal at a current set value or setting the duty ratio thereof at a value higher than the currently set value when an AC magnetic field is detected at the AC magnetic field detecting step.
Further, the timepiece device control method for controlling the timepiece device, which has a power storing unit for storing electric power supplied from the electromagnetic generator, according to the sixth aspect of the present invention further comprises a charge detecting step of detecting charging of the storing device. The AC magnetic field detecting step comprises a step of detecting an AC magnetic field generated around the electromagnetic generator when charging is detected in the predetermined time period for detection at the charge detecting step.
Moreover, the timepiece device control method according to the sixth aspect of the present invention may further have a rotation detecting step of detecting whether or not the motor rotates, and a correction driving pulse output step of outputting a correction driving pulse signal, whose effective power level is higher than that of the normal driving pulse signal, when it is detected that the motor does not rotate.
Furthermore, the method according to the sixth aspect of the present invention may further comprise a demagnetizing pulse output step of outputting a demagnetizing pulse signal to be used to demagnetize a residual magnetic field caused by the correction driving pulse signal that is outputted at the correction driving pulse signal output step.
Further, in the case of the method according to the sixth aspect of the present invention, a start time of the predetermined time period for detection is a demagnetizing-pulse outputting moment, at which a demagnetizing pulse signal is outputted in the last hand movement operation time period, or included in a time period from a moment, which is just after the demagnetizing-pulse outputting moment, to a moment just before a normal driving pulse signal is outputted in a current hand movement operation time period. Moreover, a termination time of the predetermined time period for detection is included in a time period from the moment, which is just before a normal driving pulse signal is outputted in the current hand movement operation time period, to a moment just after the normal driving pulse signal is outputted.
Furthermore, the duty ratio setting step of the method according to the sixth aspect of the present invention may have a step of maintaining the duty ratio of a pulse, which is not outputted yet, at a currently set value or setting the duty ratio of the pulse, which is not outputted yet, at a value that is higher than the currently set value.
Further, the method according to the sixth aspect of the present invention may further comprises a voltage detecting step of detecting the voltage of the power storing unit, and a teeth number selection step of selecting and changing the number of pulses of a normal driving pulse signal to be outputted in a time period therefor by comparing the voltage detected at the voltage detecting step with a predetermined reference voltage.
Moreover, the teeth number selection step of the method according to the sixth aspect of the present invention may have a step of selecting one of two numbers of pulses, which are switched from each other according to whether or not the detected voltage is higher than the reference voltage. That is, the teeth number selection step may have a step of selecting a larger one of the two number of pulses when the detected voltage is lower than the reference voltage. Furthermore, the teeth number selection step may have a step of selecting a smaller one of the two number of pulses when the detected voltage is higher than the reference voltage.
Furthermore, in the case of the method according to the sixth aspect of the present invention, a normal driving pulse signal corresponding to a larger one of the two numbers of pulses, which are to be switched from each other according to whether or not the detected voltage is higher than the reference voltage, is set in such a manner as to have a higher effective power level than that of a normal driving pulse signal corresponding to a smaller one of the two numbers of pulses.
According to a seventh aspect of the present invention, there is provided a timepiece device having a motor, which is driven according to electric power supplied from an electromagnetic generator. This timepiece device comprises a power storing unit for storing electric power supplied from the electromagnetic generator, a charge detecting unit for detecting charging of the power storing unit, and a duty ratio setting unit for setting a duty ratio of a normal driving pulse to be outputted to the motor at a value that is not less than a value of a predetermined set lower limit duty ratio, which is higher than a lowest duty ratio, which has a lowest value for driving the motor, when charging is detected by the charge detecting unit.
Further, the device according to the seventh aspect of the present invention may further comprises a motor rotation detecting unit for detecting whether or not the motor rotates. Moreover, this device performs an operation of lowering the effective power of a normal driving pulse signal when a rotation of the motor is detected by the motor rotation detecting unit, while this device performs an operation of increasing the effective power of a normal driving signal when it is detected by the motor rotation detecting unit that the motor does not rotate.
Furthermore, the rotation detecting unit of the device according to the seventh aspect of the present invention detects according to electric current induced by the rotation of the pulse motor whether or not the pulse motor rates.
According to an eighth aspect of the present invention, there is provided a timepiece device having a motor, which is driven according to electric power supplied from an electromagnetic generator. This timepiece device comprises a power storing unit for storing electric power supplied from the electromagnetic generator, and a duty ratio setting unit for setting a duty ratio of a normal driving pulse to be outputted to the motor at a value that is not less than a value of a predetermined set lower limit duty ratio, which is higher than a lowest duty ratio, which has a lowest value for driving the motor, when charging is detected by the charge detecting unit.
Further, the device according to the eighth aspect of the present invention further comprises a non-charging time counter unit for counting a non-charging time according to a result of a detection by a charge detecting unit and for stopping counting the non-charging time when the counted non-charging time is not less than a predetermined time.
Moreover, in the device according to the eighth aspect of the present invention, the non-charging time counter unit may output a carrying mode setting signal, which indicates that the timepiece device is in a carrying mode, when the counted non-charging time is less than the predetermined time. Further, the duty ratio setting unit may set the duty ratio at a value, which is not less than the set lower limit duty ratio, when the carrying mode setting signal is inputted thereto.
Furthermore, in the device according to the eighth aspect of the present invention, the non-charging time counter unit may output a non-carrying mode setting signal, which indicates that the timepiece device is in a carrying mode, when the counted non-charging time is not less than the predetermined time. Further, the duty ratio setting unit may set the duty ratio at a value, which is not less than the set lower limit duty ratio, when the non-carrying mode setting signal is inputted thereto.
Moreover, the duty ratio setting unit of the device according to the eighth aspect of the present invention may change the set lower limit duty ratio to a second set lower limit duty ratio, which is lower than the former set lower limit duty ratio and is not less than the lowest duty ratio, when the non-charging time counted by the non-charging time counter unit is not less than the predetermined time.
Further, the device according to the eighth aspect of the present invention may further comprises a rotation detecting unit for detecting whether or not the motor rotates, and a correction driving pulse output unit for outputting a correction driving pulse signal, whose effective power level is higher than that of the normal driving pulse signal, when it is detected that the motor does not rotate.
According to a ninth aspect of the present invention, there is provided a timepiece device control method for controlling a timepiece device, which is adapted to drive the motor according to electric power supplied from an electromagnetic generator and has a power storing unit for storing electric power supplied therefrom, comprises a charge detecting step of detecting charging of the power storing unit, and a duty ratio setting step of setting a duty ratio of a normal driving pulse signal to be outputted to the motor and setting the duty ratio at a predetermined value being higher than the lowest duty ratio, which has a lowest value for driving the motor, when charging is detected at the charge detecting step.
Further, the method according to the ninth aspect of the present invention further comprises a non-charging time counter step of counting a non-charging time according to a result of a detection by the charge detecting step and stopping counting the non-charging time when the counted non-charging time is not less than a predetermined time.
Moreover, in the method according to the ninth aspect of the present invention, the non-charging time counter step may have a step of outputting a carrying mode setting signal, which indicates that the timepiece device is in a carrying mode, when the counted non-charging time is less than the predetermined time. Further, the duty ratio setting step may have a step of setting the duty ratio at a value, which is not less than the set lower limit duty ratio, when the carrying mode setting signal is inputted thereto.
Furthermore, in the method according to the ninth aspect of the present invention, the non-charging time counter step may have a step of outputting a carrying mode setting signal, which indicates that the timepiece device is in a noncarrying mode, when the counted non-charging time is less than the predetermined time. Further, the duty ratio setting step may have a step of setting the duty ratio at a value, which is not less than the set lower limit duty ratio, when the noncarrying mode setting signal is inputted thereto.
Furthermore, the duty ratio setting step of the method according to the ninth aspect of the present invention may have a step of changing the set lower limit duty ratio to a second set lower limit duty ratio, which is lower than the former set lower limit duty ratio and is not less than the lowest duty ratio, when the non-charging time counted by the non-charging time counter unit is not less than the predetermined time.
Moreover, the method according to the ninth aspect of the present invention may further comprises a rotation detecting step of detecting whether or not the motor rotates, and a correction driving pulse output step of outputting a correction driving pulse signal, whose effective power level is higher than that of the normal driving pulse signal, when it is detected that the motor does not rotate.